Llorente started his career with Athletic Bilbao, working his way through the various youth ranks, and becoming one of the most important offensive players for the club in the following decade, since making his first team debut in 2005. He scored 29 goals for the club in all competitions in the 2011–12 season, and was described as a "Bilbao legend".[3] In 2013 he signed with Juventus, winning the Serie A in his first year.

On 13 July 2006 Llorente signed a new contract with Athletic until June 2011, which included a buy-out clause of between €30 and 50 million.[17] He started the season as arguably the club's fourth-choice striker, behind Aritz Aduriz, Joseba Etxeberria and veteran Ismael Urzaiz. Athletic's poor form and lack of goals led to coach Félix Sarriugarte rotating the players, allowing Llorente to force his way back into the side; he ended the campaign with only two goals in 23 matches, although he did score an important one in the closing minutes of a 1–1 draw at Valencia CF.[18]

In preparation for the 2007–08 season, Llorente scored six goals in as many pre-season games, and another against CD Numancia in the Caja Duero Trophy. His form led to him becoming Athletic's first-choice forward, and although he started the season poorly, he ended it with a total of 11 league goals for a side that finished in mid-table. His tally included four goals in two games against Valencia, both impressive wins,[19][20] and further strikes against FC Barcelona,[21]Villarreal CF[22] and Atlético de Madrid.[23]

Prior to 2008–09, Llorente was confident of a successful season. "I know that I am capable of scoring goals and having a good year and I want to start this term in the same form that I ended the last one in" he said.[24] Despite the team's modest start to the season he netted 14 league goals – a career-best – with another four in the Cup, helping his team reach the final against Barcelona (1–4 loss).

In the 2009–10 season, Llorente again reached double figures. He led all scorers in the Europa League for a lengthy period, with eight goals and added 14 in the league as Athletic finished in eighth position.

In January/February 2012, in two away games separated by only four days, Llorente scored five goals: he started with a hat-trick in a 3–2 win against Rayo Vallecano,[26] adding two in Athletic's 2-1 win over CD Mirandés in the Spanish Cup semifinals.[27] In the next two matches, both at home, he netted three more, one against Espanyol in the league[28] and two against Mirandés.[29]

In August 2012 Llorente refused to sign a new deal with Athletic Bilbao, fuelling speculation that he might be leaving the club.[3] Following a 0–2 derby loss at Real Sociedad on 29 September, in which he was a late substitute, he got into an argument with manager Marcelo Bielsa; two days later he walked out of training early and was sent to practice with the youth squad[33] and, as a result, his relationship with the club's supporters and president Josu Urrutia further deteriorated.[34]

On 3 January 2013, Athletic confirmed that Llorente would be holding contract talks with Juventus.[35] On the 21st the Italians' sporting director, Giuseppe Marotta, revealed that he was "very optimistic" that the player would join on 1 July, with Bilbao president Josu Urrutia believed to be unwilling to allow him to leave in the January transfer window.[36] Three days later the club formalized the signing, and announced he would sign a four-year contract on 1 July when his contract with Bilbao expired;[37] Juventus also paid his agent €3.038 million.[38]

Llorente (right) before a Champions League match against Real Madrid in 2013

Llorente officially became a Juventus player on 1 July 2013 after passing a medical at the club.[41][42] He was given the number 14 jersey,[40][43] and netted his first goal in Serie A on 22 September, starting in a 2–1 home win against Hellas Verona FC.

Llorente's first two goals of 2014 came on 12 January, scoring from a header and from close range as Juventus defeated 4–1 Cagliari Calcio away to extend its winning league run to 11 matches.[48] On 7 April, he netted both of his team's goals in a 2−0 home success over A.S. Livorno Calcio, confirming a top-two finish;[49] on the final day of the season, again against Cagliari, he contributed with one goal as the hosts won it 3–0 to become the team with the most points in a single Serie A campaign with 102.[50]

During the 2009–10 season, Llorente was not called-up once, as del Bosque favoured Álvaro Negredo. He would, however, be selected for the 2010 FIFA World Cup, also in South Africa, as third-choice striker, where he played in one match for the eventual champions, the last 30 minutes of the 1–0 round-of-16 win against Portugal.

On 8 October 2010, benefiting from an injury to Fernando Torres, Llorente started in a UEFA Euro 2012qualifier against Lithuania, in Salamanca. With two headers – his strongest asset – he contributed prominently in a 3–1 win. Four days later, as a substitute, he scored the winner against Scotland in a 3–2 success at Hampden Park. He was selected for the final stages in Poland and Ukraine, being an unused squad member as Spain won another tournament.

A physical player, Llorente's main trait is his heading ability.[65] In addition, he is also gifted with good skills, which allows him to play with his back to goal and hold up the ball for his team mates to create space and scoring opportunities.[66]